This invention relates to the refining of ferrochromium metal and, more particularly, to the refining of high carbon ferrochromium metal to remove some carbon therefrom and also reduce the silicon content.
In the past, refining of silicon and carbon in ferrochromium metal by the addition of metal oxides has, apart from by gas injection processes such as Argon-oxygen decarburization (A.O.D.), only been achieved in the solid state under considerable vacuum in the so-called simplex process.
In this specification the term "fines" is intended to mean subdivided material having a size of less than 6 mm and includes sizes of less than 2 mm which is, in many cases, considered unsaleable in respect of certain material such as ferrochromium, for example. It is the object of this invention to provide an improved refining process for ferrochromium metal.
Furthermore, a transferred arc thermal plasma is defined as an electrically generated plasma in which the ion temperature lies in the range 5000 K to 60,000 K and the molten bath forms a substantial part of the electrical circuit.